.Nm lstat ,
.Nm lstat64 ,
.Nm stat ,
-.Nm stat64
+.Nm stat64 ,
+.Nm fstatat
.Nd get file status
.Sh SYNOPSIS
.Fd #include <sys/stat.h>
.Fa "const char *restrict path"
.Fa "struct stat *restrict buf"
.Fc
+.Ft int
+.Fn fstatat "int fd" "const char *path" "struct stat *buf" "int flag"
.Sh TRANSITIIONAL SYNOPSIS (NOW DEPRECATED)
.Ft int
.br
while
.Fn stat
returns information about the file the link references.
-Unlike other filesystem objects,
-symbolic links may not have an owner, group, access mode, times, etc.
-Instead, these attributes may be taken from the directory that
-contains the link.
+The attributes cannot be relied on in case of symbolic links.
In this case, the only attributes returned from an
.Fn lstat
that refer to the symbolic link itself are the file type (S_IFLNK),
.Fa fildes .
.Pp
The
+.Fn fstatat
+system call is equivalent to
+.Fn stat
+and
+.Fn lstat
+except in the case where the
+.Fa path
+specifies a relative path.
+In this case the status is retrieved from a file relative to
+the directory associated with the file descriptor
+.Fa fd
+instead of the current working directory.
+.Pp
+The values for the
+.Fa flag
+are constructed by a bitwise-inclusive OR of flags from the following list,
+defined in
+.In fcntl.h :
+.Bl -tag -width indent
+.It Dv AT_SYMLINK_NOFOLLOW
+If
+.Fa path
+names a symbolic link, the status of the symbolic link is returned.
+.El
+.Pp
+If
+.Fn fstatat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa fd
+parameter, the current working directory is used and the behavior is
+identical to a call to
+.Fn stat
+or
+.Fn lstat
+respectively, depending on whether or not the
+.Dv AT_SYMLINK_NOFOLLOW
+bit is set in
+.Fa flag .
+.Pp
+The
.Fa buf
argument is a pointer to a
.Fa stat
and into which information is placed concerning the file.
When the macro
.Dv _DARWIN_FEATURE_64_BIT_INODE
-is not defined (the
-.Ft ino_t
-type is 32-bits), the
+is not defined (see below for more information about this macro), the
.Fa stat
structure is defined as:
.Bd -literal
dev_t st_dev; /* device inode resides on */
ino_t st_ino; /* inode's number */
mode_t st_mode; /* inode protection mode */
- nlink_t st_nlink; /* number or hard links to the file */
+ nlink_t st_nlink; /* number of hard links to the file */
uid_t st_uid; /* user-id of owner */
gid_t st_gid; /* group-id of owner */
dev_t st_rdev; /* device type, for special file inode */
However, when the macro
.Dv _DARWIN_FEATURE_64_BIT_INODE
is defined, the
-.Ft ino_t
-type will be 64-bits (force 64-bit inode mode by defining the
-.Dv _DARWIN_USE_64_BIT_INODE
-macro before including header files).
-This will cause symbol variants of the
-.Fa stat
-family, with the
-.Fa $INODE64
-suffixes, to be automatically linked in.
-In addition, the
.Fa stat
structure will now be defined as:
.Bd -literal
.It st_birthtime
Time of file creation. Only set once when the file is created. This field is
only available in the 64 bit inode variants. On filesystems where birthtime is
-not available, this field holds the
-.Fa ctime
-instead.
+not available, this field is set to 0 (i.e. epoch).
.El
.Pp
The size-related fields of the structures are as follows:
.Aq Pa sys/stat.h
and
.Xr chflags 2 .
+.Sh _DARWIN_FEATURE_64_BIT_INODE
+In order to accommodate advanced capabilities of newer file systems, the
+.Fa struct stat ,
+.Fa struct statfs ,
+and
+.Fa struct dirent
+data structures were updated in Mac OSX 10.5.
+.Pp
+The most obvious change is the increased size of
+.Fa ino_t
+from 32 bits to 64 bits. As a consequence, storing an ino_t in an int is
+no longer safe, and file formats storing ino_t as 32-bit values may need to
+be updated. There are other changes as well, such as the widening of
+.Fa f_fstypename ,
+.Fa f_mntonname ,
+and
+.Fa f_mntfromname
+in
+.Fa struct statfs .
+Please refer to
+.Xr stat 2
+and
+.Xr dir 5
+for more detail on the specific changes to the other affected data structures.
+.Pp
+On platforms that existed before these updates were available, ABI
+compatibility is achieved by providing two implementations for related
+functions: one using the legacy data structures and one using the updated
+data structures. Variants which make use of the newer structures have their
+symbols suffixed with $INODE64. These $INODE64 suffixes are automatically
+appended by the compiler tool-chain and should not be used directly.
+.Pp
+Platforms that were released after these updates only have the newer variants
+available to them. These platforms have the macro
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE
+defined.
+.Pp
+The
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+macro should not be set directly. Instead, developers should make use of the
+.Dv _DARWIN_NO_64_BIT_INODE
+or
+.Dv _DARWIN_USE_64_BIT_INODE
+macros when the default variant is not desired. The following table details
+the effects of defining these macros for different deployment targets.
+.Pp
+.TS
+center;
+c s s s
+l | c s s
+c | c c c
+c | c c c
+l | c c c.
+T{
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE Sy not defined
+T}
+=
+ Deployment Target
+user defines: < 10.5 10.5 > 10.5
+_
+T{
+.Em (none)
+T} 32-bit 32-bit 64-bit
+T{
+.Dv _DARWIN_NO_64_BIT_INODE
+T} 32-bit 32-bit 32-bit
+T{
+.Dv _DARWIN_USE_64_BIT_INODE
+T} 32-bit 64-bit 64-bit
+_
+.T&
+c s s s
+c s s s
+c | l s s
+c | c c c
+l | c c c.
+
+T{
+.Dv _DARWIN_FEATURE_ONLY_64_BIT_INODE Sy defined
+T}
+=
+user defines: Any Deployment Target
+_
+T{
+.Em (none)
+T} 64-bit-only
+T{
+.Dv _DARWIN_NO_64_BIT_INODE
+T} T{
+.Em (error)
+T}
+T{
+.Dv _DARWIN_USE_64_BIT_INODE
+T} 64-bit-only
+_
+.TE
+.Pp
+.Bl -tag -width 64-bit-only -offset indent
+.It 32-bit
+32-bit inode values are enabled, and the legacy structures involving the
+.Vt ino_t
+type are in use.
+The macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is not defined.
+.It 64-bit
+64-bit inode values are enabled, and the expanded structures involving the
+.Vt ino_t
+type are in use.
+The macro
+.Dv _DARWIN_FEATURE_64_BIT_INODE
+is defined, and loader symbols will contain the
+.Li $INODE64
+suffix.
+.It 64-bit-only
+Like 64-bit, except loader symbols do not have the
+.Li $INODE64
+suffix.
+.It Em (error)
+A compile time error is generated.
+.El
+.Pp
+Due to the increased benefits of the larger structure, it is highly
+recommended that developers not define
+.Dv _DARWIN_NO_64_BIT_INODE
+and make use of
+.Dv _DARWIN_USE_64_BIT_INODE
+when targeting Mac OSX 10.5.
+.Pp
+In addition to the $INODE64 suffixed symbols, variants suffixed with 64 are
+also available for related functions. These functions were provided as a way
+for developers to use the updated structures in code that also made use of
+the legacy structures. The enlarged stat structures were also prefixed with
+64 to distinguish them from their legacy variants. These functions have been
+deprecated and should be avoided.
.Sh RETURN VALUES
Upon successful completion a value of 0 is returned.
Otherwise, a value of -1 is returned and
in the structure pointed to by
.Fa buf .
.El
+.Pp
+In addition to the errors returned by the
+.Fn stat
+and
+.Fn lstat ,
+.Fn fstatat
+may fail if:
+.Bl -tag -width Er
+.It Bq Er EBADF
+The
+.Fa path
+argument does not specify an absolute path and the
+.Fa fd
+argument is neither
+.Dv AT_FDCWD
+nor a valid file descriptor open for searching.
+.It Bq Er EINVAL
+The value of the
+.Fa flag
+argument is not valid.
+.It Bq Er ENOTDIR
+The
+.Fa path
+argument is not an absolute path and
+.Fa fd
+is neither
+.Dv AT_FDCWD
+nor a file descriptor associated with a directory.
+.El
.Sh CAVEATS
The file generation number,
.Fa st_gen ,
.Xr chown 2 ,
.Xr utimes 2 ,
.Xr compat 5 ,
+.Xr statfs 2 ,
.Xr symlink 7
.Sh BUGS
Applying
.Fn fstat
function calls are expected to conform to
.St -p1003.1-88 .
+The
+.Fn fstatat
+system call is expected to conform to POSIX.1-2008 .
.Sh HISTORY
An
.Fn lstat
.Fn lstat64
system calls first appeared in Mac OS X 10.5 (Leopard) and are now deprecated
in favor of the corresponding symbol variants.
+The
+.Fn fstatat
+system call appeared in OS X 10.10
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